Field of the Invention
The present invention relates to a display device, and more particularly, to a display device including an interface device that effectively transmits data technology during communication between a display module and an external circuit.
Discussion of the Related Art
Examples of flat display devices recently highlighted as display devices to display images using digital data include a liquid crystal display (LCD) using liquid crystals, and an organic light emitting diode (OLED) display using OLEDs. An organic light emitting diode (OLED) display device is a self-luminous device in which an organic light emitting layer emits light through re-combination of electrons and holes. Because the OLED display device exhibits high luminance, uses a low drive voltage, and has a slim profile, the OLED display device is expected to be a next-generation display device.
Such an OLED display device includes a plurality of pixels, each of which includes an OLED having an anode, a cathode, and an organic light emitting layer interposed between the anode and the cathode, and a pixel circuit for independently driving the OLED. The pixel circuit includes a switching thin film transistor (TFT) for supplying a data voltage to a storage capacitor, a drive TFT for controlling drive current in accordance with a drive voltage charged in the storage capacitor and supplying the controlled drive current to the OLED. The OLED generates light having a light amount proportional to the amount of the drive current.
In related art OLED display devices, however, a non-uniformity of luminance may occur as a result of deviations in driving characteristics (e.g., threshold voltage and mobility) of drive TFTs among pixels due to process deviation and passage of time. To solve such a problem, OLED display devices use an external compensation method for sensing driving characteristics of each pixel, and compensating data to be supplied to the pixel using the sensed value.
OLED display devices are applicable to various products, such as portable terminals, TV sets, flexible displays, and transparent displays. Recent advances in OLED display devices have focused on reducing thickness for application to a paper display or a wallpaper display.
To reduce thickness of a display module in an OLED display device, a scheme to externally separate a part of circuit configurations mounted in the display module should be taken into consideration. In this case, an encrypted transmission system is required to protect contents during communication between the display module and the separated circuit configuration.
In particular, when an interface using the encrypted transmission system is used, a scheme for transmitting sensing data required for external compensation of the OLED display device without data loss should also be taken into consideration. In addition, because the transmission cable between the externally separated circuit and the display module is externally exposed, a scheme for reducing the thickness of the cable should be taken into consideration for an improved design.